Presentation Details
| Phasic Gut Feedback Shapes Flavor-Nutrient Learning Kevin P.Myers. Bucknell University, Lewisburg, PA, USA |
Abstract
It has been a longstanding view that macronutrient molecules (especially sugars and fats) have palatable orosensory properties that stimulate food intake, but that their post-oral effects are generally inhibitory, triggering negative feedback signals that cause meal termination. However, a body of evidence has recently emerged establishing that nutrients sensed in the gut can give rise to immediate positive feedback signals (termed ‘appetition,’ in contrast to the better-understood ‘satiation’ signals) that stimulate ongoing intake, increase meal size, and produce learned preferences for tastes and flavors in the meal. This presentation will provide an overview of the behavioral properties of appetition, including evidence from our work in a rat model that within the first several minutes of a meal, animals psychologically ‘attribute’ gut nutrient sensing to the specific flavor of the food they are currently consuming. Although appetition acts to increase intake and steer preference towards nutrient-dense foods, the relationship between appetition, flavor-nutrient learning, and diet-induced obesity is complex. We have found that with long-term access to high-fat/sugar diet, rats who gain the most weight also show the strongest appetition responses, including both immediate intake stimulation by gut nutrient infusion and learned preference for nutrient-paired flavors. However, rats selectively bred to be highly prone or resistant to diet-induced obesity show no differences in appetition responses prior to obesogenic diet access, suggesting that sensitized appetition is a consequence, not a cause, of chronic overeating and/or obesity. The presentation will conclude with an overview of some important unanswered questions about the psychology and neurobiology of appetition.
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No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author.